regex.cpp

Boost.Regex and std::regex usage example

See also

Regular expression (Wikipedia)

// Copyright (c) 2017 Kolya Kosenko
 
// Distributed under the Boost Software License, Version 1.0.
// See http://www.boost.org/LICENSE_1_0.txt
 
// Show C++11 Regex or Boost.Regex work using user data.
 
#include <boost/ui.hpp>
 
#if !defined(BOOST_NO_CXX11_HDR_REGEX)
#include <regex>
namespace regex_ns = std;
#else
#include <boost/regex.hpp>
namespace regex_ns = boost;
#endif
 
namespace ui = boost::ui;
 
class regex_dialog : public ui::dialog
{
    typedef regex_dialog this_type;
 
public:
    regex_dialog();
 
private:
    void on_match(bool entire);
    void on_replace();
 
    regex_ns::wregex get_pattern() const;
 
    ui::text_box m_input;
    ui::text_box m_output;
    ui::string_box m_pattern;
    ui::string_box m_format;
    ui::check_box m_case_sensetive;
};
 
regex_dialog::regex_dialog() : ui::dialog(
#if !defined(BOOST_NO_CXX11_HDR_REGEX)
    "C++11 "
#else
    "Boost."
#endif
    "Regex + Boost.UI example")
{
    ui::vbox(*this)
        << m_input.create(*this, "Hello, World!")
            .tooltip("Input data")
            .layout().stretch().justify()
        << (ui::hbox().layout().justify()
            << m_pattern.create(*this, "(\\w+)[ ,]+(\\w+)(.*)")
                .tooltip("Regex pattern")
                .layout().stretch()
            << m_case_sensetive.create(*this, "&Case sensetive")
                .check()
           )
        << (ui::hbox().layout().justify()
            << ui::button(*this, "&Search")
                .on_press(&this_type::on_match, this, false)
                .tooltip("Searches any part of a sequence")
            << ui::button(*this, "&Match")
                .on_press(&this_type::on_match, this, true)
                .tooltip("Searches an entire sequence")
            << ui::button(*this, "&Replace")
                .on_press(&this_type::on_replace, this)
                .tooltip("Replaces occurrences with formatted text")
           )
        << (ui::hbox().layout().justify()
            << ui::label(*this, "Format:").layout().margin(1, 0, 1, 1)
            << m_format.create(*this, "[$&]")
                .layout().stretch()
           )
        << m_output.create(*this).tooltip("Output data")
            .layout().stretch(2).justify()
        ;
 
    resize(400, 400);
}
 
void regex_dialog::on_match(bool entire)
{
    const std::wstring input = m_input.text().wstring();
    const regex_ns::wregex pattern = get_pattern();
 
    m_output.clear();
    regex_ns::wsmatch results;
 
    if ( entire )
    {
        if ( !regex_ns::regex_match(input, results, pattern) )
            return;
    }
    else
    {
        if ( !regex_ns::regex_search(input, results, pattern) )
            return;
    }
 
    std::wostringstream ss;
    ss << L"prefix: \"" << results.prefix() << "\" ( $` )\n";
    ss << L"suffix: \"" << results.suffix() << "\" ( $' )\n";
    for ( regex_ns::wsmatch::const_iterator iter = results.begin();
            iter != results.end(); ++iter )
    {
        const regex_ns::wssub_match sub_match = *iter;
        const regex_ns::wsmatch::difference_type i =
            std::distance(results.begin(), iter);
        ss << L'$' << i << L": \"" << sub_match << L'"';
        if ( i == 0 )
            ss << L" ( $& )";
        ss << std::endl;
    }
    ss << L"format: \"" << results.format(m_format.text().wstring()) << "\"";
    m_output.text(ss.str());
}
 
void regex_dialog::on_replace()
{
    const std::wstring input = m_input.text().wstring();
    const regex_ns::wregex pattern = get_pattern();
    m_output.text(regex_ns::regex_replace(
        input, pattern, m_format.text().wstring() ));
}
 
regex_ns::wregex regex_dialog::get_pattern() const
{
    regex_ns::wregex re = regex_ns::wregex(m_pattern.text().wstring(),
                                           m_case_sensetive.is_checked()
        ? regex_ns::regex_constants::ECMAScript
        : regex_ns::regex_constants::ECMAScript|regex_ns::regex_constants::icase);
 
    //re.imbue(ui::getloc());
 
    return re;
}
 
int ui_main()
{
    regex_dialog().show_modal();
 
    return 0;
}
 
int main(int argc, char* argv[])
{
    return ui::entry(&ui_main, argc, argv);
}